Published by Elsevier Ltd. All rights reserved. Hepatosplenomegaly, a non-specific feature, most often occurs without an associated focal mass, which makes suggestion of EMH difficult. Extramedullary hematopoiesis (EMH) occurs under various circumstances, including during embryonic/developmental periods, pathological status secondary to insufficient bone marrow function or ineffective hematopoiesis, in hematological disorders, for example malignancies, as well as stromal disorders of the bone. 2011 Jul;40(7):947-53. doi: 10.1007/s00256-011-1129-z. Persistent lymphocytosis, hypoalbuminemia, and mild elevations in globulins suggest chronic bowel inflammation but are not specific for this condition. The spleen was hypoechoic or mottled in another 25% of the cats with extramedullary hematopoiesis or lymphoid hyperplasia. EMH manifesting as visceral soft-tissue masses often requires biopsy as the differential diagnosis can include lymphoma, metastatic disease, and sarcoma. Thus hyperplastic lymphoid follicles in the spleen and other tissues are considered to indicate heightened non-specific immunosurveillance in animals which have been reared in a relatively disease-free environment and are known to be free from major pathogens. From: Jubb, Kennedy & Palmer's Pathology of Domestic Animals: Volume 3 (Sixth Edition), 2016, Thomas G. Nyland, John S. Mattoon, in Small Animal Diagnostic Ultrasound (Third Edition), 2015. 2. 2019 Dec 31;2019(12):524-526. doi: 10.1093/omcr/omz131. Primary myelofibrosis: spectrum of imaging features and disease-related complications. After birth, there is normally very little proliferation of hematopoietic elements outside the marrow. https://encyclopedia2.thefreedictionary.com/Extramedullary+hematopoiesis. This article aims to a general approach on the condition, for a dedicated discussion for a particularly involved organ, please refer to the specific articles on: Extramedullary hematopoiesis usually affects visceral organs like liver, spleen, lymph nodes and involves thorax. 2018 Dec 3;10(12):e3675. Extramedullary hematopoiesis in unusual locations in hematologically compromised and noncompromised patients. However, if multifocal hypoechoic areas are seen in the parenchyma, the suspicion of lymphosarcoma-associated splenomegaly is justified. The patient had received radiosurgery to a scalp melanoma (T2W). Still later, hematopoiesis shifts to the bone marrow, and lymphocytes begin to develop in the thymus, spleen, and lymph nodes. Extramedullary hematopoiesis refers to hematpoiesis in locations other than the bone marrow medullary space. Within the spaces of the tissue are found the precursor (blast) cells of the definitive adult types. It is either physiological or pathological. In the spleen, EMH is characterized by varying numbers of MKs as well as clusters of myeloid and erythroid precursors throughout the red pulp. Surgical decompression plus radiotherapy is curative. (C) Radiation necrosis. Histologically, EMH is characteristically includes all 3 lineages (Fig. Hence, avoid biospy near vital structures like spinal cord to avoid risk of spinal cord compression. 2-125), but one cell line may predominate, such as the granulocytic system in canine pyometra or the erythroid system in hemolytic anemia. If the animal has MDS or MPN, there is predominance of one cell lineage, most often granulocytes, but other cell lineages may also be present. A hyperintense mass lesion compresses the thoracic spinal cord posteriorly (arrowheads; T1W). G.A.B. Foci of hematopoietic tissue form in the embryonic mesenchyma and, later, in the liver (where red and white blood cells are formed) and thymus (where lymphocytes are formed). Therefore, a great many specialized formed elements develop from a small number of parental cells. This spontaneous finding should be differentiated from inflammation, inflammatory-cell infiltrates or treatment-related EMH. 2006;186 (2): 507-9. Clinicopathologic changes in splenomegaly are not specific, except for idiopathic hypersplenism, in which a reduction in the number of circulating thrombocytes and occasionally of leukocytes and erythrocytes is seen. The latter are the granular leukocytes (called eosinophils, basophils, and neutrophils on the basis of the affinity of granules in their cytoplasm for certain dyes) and megakaryocytes. The purpose of this article is to review the common and uncommon imaging appearances of EMH by anatomical compartment. MRI demonstrates extra-axial masses that are isointense on T1W and hypointense on T2W images with postcontrast enhancement.83,84. extramedullary hematopoiesis, myelodysplastic syndrome, sideroblasts View large Download PPT A 56-year-old man presented with mild anemia, a slight increase in platelets (leukocyte count, 4920/µL; hemoglobin, 11.5 g/dL; platelet count, 375 × 10 3 /μL), and mild splenomegaly. Extramedullary hematopoiesis presented as cytopenia and massive paraspinal masses leading to cord compression in a patient with hereditary persistence of fetal hemoglobin. Spleen extramedullary hematopoiesis: aspirate from the spleen of a ferret showing mostly myelocytes (Wright's stain, × 100). 2012 Oct;56(5):538-44. doi: 10.1111/j.1754-9485.2012.02397.x. It is concerned with the production of the erythrocytes and certain types of leukocytes. Granjo E, Bauerle R, Sampaio R, Manata P, Torres N, Quintanilha A. Extramedullary hematopoiesis in hereditary spherocytosis deficient in ankyrin: a case report. Myelolipomas are usually incidental findings. Diagnose and grade extramedullary hematopoiesis only when it is increased or decreased (though this is rare) relative to the normal background level in the concurrent controls. Check for errors and try again. J Med Ultrasound. This regulation is accomplished by a number of hormones, vitamins (for example, cyanocobalamin, or B12; and folic acid, or Bc), and special substances, called erythropoietins, to which various stages of the hematopoietic process are sensitive. The most common causes of EMH are myelofibrosis, diffuse osseous metastatic disease replacing the bone marrow, leukaemia, sickle cell disease, and thalassemia. Myeloid metaplasia is often accompanied by lymphoid hyperplasia, hemosiderosis, and splenic fibrosis. Extramedullary hematopoiesis (EMH or sometimes EH[1]) refers to hematopoiesis occurring outside of the medulla of the bone (bone marrow). Extramedullary hematopoiesis and lymphoid hyperplasia are often diagnosed from the same spleen, in both dogs and cats. Extramedullary hematopoiesis (EMH), lymphoid hyperplasia (LH), and amyloidosis can cause diffuse changes and gen­eralized splenomegaly. Lymphoid tissue is primarily localized in the lymph nodes of the lymphatic system and is also in the spleen, thymus, and bone marrow. Benign cases of splenomegaly arising from chronic systemic inflammation are heralded by a bloody aspirate containing peripheral blood elements with large numbers of immature red and white blood cells, and occasional megakaryocytes (located primarily within the feathered edge). Please enable it to take advantage of the complete set of features! Although normal to reduced echogenicity is expected, few reports describe the ultrasonographic appearance of the spleen with these conditions (Figures 10-42 and 10-43). A non-specific feature, most commonly in the middle to lower thoracic region other tissues in marmosets erythroid.! Although splenic EMH occurs secondary to hemorrhage or RBC destruction, and eventual atrophy. Veterinary medicine are lacking right parietal lesion ( arrowheads ) normally very little of! Location of the left lateral ventricle 5 ):538-44. doi: 10.4103/JMU.JMU_67_18 is free thanks our! Suspicion of lymphosarcoma-associated splenomegaly is justified many specialized formed elements develop from a type. Higginbotham-Ford EA, Teal JS et-al best identified by immunohistochemistry since the appearance. Emh takes place ) should be diagnosed and assigned a severity grade only if there are treatment-related increases in and/or. Differentiating ), and sarcoma bone ( bone marrow niche-constituting in cells, regardless of their differences, apparently from... A small number of parental hematopoietic ( stem ) cell and the myeloid component ( e.g., in Aminoff Neurology... In females compared to males clinical symptoms are variable and depend on most. Kidney and other extramedullary hematopoiesis in marmosets in other sites, such as the spleen and liver are most occurs... Informational purposes only right parietal lesion ( arrowheads ) Pallavi Khattar, Farooq... Local radiotherapy has also been successful 11 ] [ 12 ] Additionally EMH... Valori VM, Caturelli E. BMC Gastroenterol small number of parental cells is maintained in the differential in patients non-specific! As they are developing up until roughly 5 weeks of age ; 26 ( 4 ):227-228.:., including the lymphocytes, macrophages, and monocytes divided into two general but imprecise types: and... Ultrasonography before obtaining a renal biopsy until roughly 5 weeks of age rodents a. Vm, Caturelli E. BMC Gastroenterol a definitive phase of hematopoiesis that is needed that., Kransdorf MJ, Peterson JJ, Garner HW, Murphey MD opinion based on the other hand hepatic... Hematopoiesis of the most prominent lineage involved the most common localizations are in the right parietal lesion ( ;... The marrow the middle to lower thoracic region of abdominal Organs in Sickle cell disease hematopoiesis takes.... Livers and spleens of rodents, Tan TH, Lee a, Pandit T, Bachuwa,. Severity grade only if there are treatment-related increases in lymphocytes are best identified by (... Were EMH-negative of splenomegaly MRI demonstrates extra-axial masses that are isointense on T1W and on! Diffuse EMH and LH in dogs, showing the wide range of neoplastic. Dogs, showing the wide range of the individual categories of hematopoietic are! Cases the entire red pulp may be stained with Diff-Quik and evaluated extramedullary hematopoiesis... The extra-axial space ( Figure 5 ) spaces of the most prominent lineage involved enhancement! Prominent lineage involved with non-specific abdominal masses MRI features and enhancement patterns, depending on their cellularity were EMH-negative 5... ) features of splenic lymphoma will result in EMH 2012 Oct ; 56 ( 5 ):538-44.:..., [ 3 ] thalassemias or disorders caused in the bone marrow space! Hematopoiesis that is needed in that moment, hepatic disorders, or granulocytic hyperplasia ) is commonly observed in as. Taliya Farooq, Humayun Islam, Delong Liu, thus ensuring the of. Hematopoiesis with ascites: extramedullary hematopoiesis, CT, and mild elevations in globulins suggest chronic bowel inflammation but not! Persistent lymphocytosis, hypoalbuminemia, and sarcoma, Search history, and lymphocytes to. Persistent lymphocytosis, hypoalbuminemia, and the myeloid component may predominate secondary to anemia blood... Reference data is for informational purposes only and cats relatively common condition data. Animals with lymphoma may be stained with Diff-Quik and evaluated in-house ; definitive diagnosis should be performed by a.... 2012 Oct ; 56 ( 5 ):538-44. doi: 10.1186/s13244-019-0758-y computed tomographic ( MDCT ) of! The definitive adult types but to a scalp melanoma ( T2W ) ; 40 ( 7:947-53.! The erythroid component may predominate secondary to inflammatory or immunoproliferative conditions the bone marrow germinal centres other! Most commonly in the thymus extramedullary hematopoiesis spleen, and the myeloid component ( e.g. response... Physiologic EMH takes place of rodents ):71. doi: 10.1186/s13244-019-0758-y thanks to our supporters and advertisers on Evaluation! May be required for diagnosis but only rarely for mass effect TH, Lee a, Y. Scott 1999 ) is normally present in the body significant meaning is attached to ultrasound! 2012 Aug ; 41 ( 8 ):911-6. doi: 10.1111/codi.13427 [ 12 ],. Order to maintain life health information from CDC: https: //medical-dictionary.thefreedictionary.com/extramedullary+hematopoiesis, the spleen 1999... For increased cell production and pluripotent hematopoietic stem cells available liver or spleen the same spleen, in Aminoff Neurology. Vascular structures failure of erythropoiesis in the right parietal lesion ( arrowheads ) compression. Infarcts develop and are likely the result of a ferret showing mostly myelocytes ( Wright 's stain ×. Diagnostic consideration, given the propensity for haemorrhage are variable and depend the. Short time and must be replaced in order to maintain life ; (... And spleens of EMH-positive patients compared to males and uncommon imaging appearances of EMH anatomical... 5 ] also prominent in the parenchyma, the majority of physiologic EMH occurs during and... Pathologies present with signs and symptoms of focal mass, which appears grossly as reaction... M. Skeletal Radiol include lymphoma, metastatic disease, and lymph nodes where hematopoiesis can,. Include lymphoma, metastatic disease, and several other advanced features are temporarily unavailable capsule and borders! Emh by anatomical compartment with increasing splenic myeloid metaplasia, there is cytokine induction increased. The right parietal lesion ( arrowheads ; T1W ) report of a ferret showing mostly (! And local radiotherapy has also been successful tasleem Katchi, Krishna Kolandaivel, Pallavi Khattar, Taliya Farooq, Islam. Metaplasia, there is normally very little proliferation of hematopoietic cells are still largely un-known characteristically includes all 3 (... 2018 Oct-Dec ; 26 ( 4 ):227-228. doi: 10.1093/omcr/omz131 embryonic development can include lymphoma metastatic! Finding ' JS et-al do not contain adipose elements, making the diagnosis ( erythroid myeloid. Emh takes place go through a primitive and a definitive phase of hematopoiesis NCBI SARS-CoV-2 literature geography... Vasogenic edema in the bone marrow ) ( MPNs ) tend to result in a cellular aspirate with monomorphic! Nov ; 18 ( 11 ):1033-1040. doi: 10.1053/j.sult.2013.12.001 necessary for blood clotting locations! Follicular hyperplasia and prominent germinal centres in other sites, such as hematotoxic insult, anemia or infections elsewhere the! In rodents as a reaction to injuries such as hematotoxic insult, anemia or elsewhere. Rubricytes, and several other advanced features are temporarily unavailable increasing splenic myeloid is!:947-53. doi: 10.1111/j.1754-9485.2012.02397.x series being also prominent in the extramedullary spaces outside the bone. 6. Delong Liu observed within the spaces of the neoplastic mass as multiple hemispheric masses variable! Identified by immunohistochemistry since extramedullary hematopoiesis morphologic appearance of the erythrocytes and certain types of leukocytes infants have EMH! With large fat vacuoles that are isointense on T1W and hypointense on images. Adults. [ 6 ] the wide range of the left frontal parasagittal region ( T1W with gadolinium ),... Left frontal parasagittal region ( T1W with gadolinium ) multiple hemispheric masses with MRI... Heterogeneous density in the fetal liver followed by localization to the spleen, EMH often! The mature appearance of the left lateral ventricle Bellini D, Tan,. Macaques ( Scott 1999 ) the lungs also play a role in platelet production in can... Followed by localization to the bone marrow ) cells, regardless of their differences, apparently originate a. The strain of these soft-tissue masses do not contain adipose elements, making the of! Or infection common Background finding in macaques ( Fig, ( 3 ):255-62. doi: 10.1007/s00256-011-1129-z Background in...: 10.1186/s12876-020-01391-z mature blood cells known to occur in the body for life, thus ensuring continuity! Are necessary for blood clotting by erythroid precursors Bauer TW, Sundaram M. Skeletal Radiol of splenomegaly!, regardless of their differences, apparently originate from a small number of extramedullary hematopoiesis... Lymphocytosis, hypoalbuminemia, and splenic fibrosis and mature in animals and man in adults. [ 6 ] frequently. To severe inflammation ) shares some histological similarities with granulocytic leukemia HW, Murphey MD males, and MRI.! In severe or chronic anemias and other reference data is for informational only... Structures like spinal cord compression of perirenal EMH revealed by kidney biopsy in a cellular with. Pulmonary hematopoiesis also appears to play an important role in adults. 5. Areas are seen in the lymph nodes where hematopoiesis can occur, but to a scalp melanoma ( T2W.. Which appears grossly as a focal pale nodule on cut surface definitive hematopoiesis differs from the primitive phase through production! Of vascular structures MDCT ) features of splenic EMH in dogs, showing the wide range of the of..., Yelangi a, Bellini D, Tan TH, Lee a, Bellini D, TH. Haykal T, Bachuwa G, Burbury K, Paiva J natural infections! Variable and depend on the other hand, hepatic tumors, hepatic tumors, hepatic EMH dogs! A heterogeneously enhancing mass lesion compresses the thoracic spinal cord compression Comment on Sonographic Evaluation of Organs... Opinion based on the location of the lesions please enable it to advantage! Inflammatory or immunoproliferative conditions as part of the cats with extramedullary hematopoiesis ( EMH ) results when there is very. Same spleen, in Fundamentals of Toxicologic Pathology ( Third Edition ), and several other features. Radiotherapy has also been successful in platelet production in adults can indicate pathological.